K)8 PROCEEDINGS OP THE ROYAL SOCIETY OF QUEENSLAND. 



being then considerably smaller than usual. If pupae be too 

 heavily parasitized, then neither wasps nor flies emerge. The 

 following numbers were obtained from six artificially infected 

 fly-pujia?, kept under observation : 29, 26, 22, 14, 11, 10. 



The freshly laid egg is rather long and somewhat irre- 

 gularly shaped, measuring -208 mm. in length and -076 mm. 

 in breadth. A small clear area can be seen at one end of the 

 otherwise granular protoplasm ; and it is here that the egg 

 membrane possesses a micropyle (fig. 16). The egg soon 

 begins to segment by the usual peripheral segmentation 

 method characteristic of insects. After 24. hours it is in a 

 high state of segmentation and the developing embryo can 

 be seen in the middle (fig. 17). The egg has by this time 

 contracted considerably, measuring only -164 mm. in length 

 by 072 mm. in breadth. Hatching appears to take place in 

 about 48 hours, but this statement is made with considerable 

 reserve. 



The larva is of the usual 14-segmented type, the nine 

 spiracles together with the tracheae being very evident (fig. 25). 

 Feeding appears to take place much in the same way as in 

 Nasonia, that is, by a suctorial action produced by the alter- 

 nate action of protrusive (sphincter) and retractile buccal 

 muscles (fig. 9). A pair of chitinous jaws, resembling those 

 of the third instar of Nasonia, are present. The midgut does 

 not communicate with the rectum luitil the end of the feeding 

 stage, when, probably after a period of resting, defiecation 

 takes place, and then after about one day the larva moults 

 and a pupa appears (fig. 26). 



The pupa is at first white in colour ; after a few days the 

 eyes redden and then the whole pupa darkens and gradually 

 develops into the adult. The full period, from oviposition to 

 emergence of the adult, occupies about 20 days in midsummer. 

 In October it was found to be 25 days, in February 21, in May 

 as much as 28 or even 30 days, the time gradually lengthening 

 between February and May as the weather became cooler. 

 In June and July it occupied approximately six weeks. 



It was found that \\hen wasps wliich had just emerged 

 from the fly-pupa were isolated they would parasitize maggots 

 as usual, and further that the offspring consisted of males 

 and females in the normal proportion, which we have ascer- 

 tained to be about 3:7. It must, therefore, be inferred that 



